This invention relates more specifically to the removal of wood particles, dirt, dust and debris from a large disc type wood chipper during the period the machine is undergoing a knife blade replacement procedure. Typically, in most large disc type chippers, a series of slots are passed through the disc and cutting blades are mounted at the front face entrance of the slots. Logs are fed into the machine so that they move in contact with the front face of the rotating disc where they come in contact with the knife blades. Chips are removed from the logs by the blades and are directed through the slots into a discharge chute that is located behind or under the disc. With time, the knife blades become dull and must be replaced with new or resharpened blades.
During the blade replacement procedure, a section of the machine casing that surrounds the disc is removed to provide access to a portion of the disc in the exposed region. The blades in this region are removed from the disc and new blades are installed, typically by a person on the front side of the disc, while a second person is often required also on the back side of the disc to conduct other disc chipper maintenance or to loosen clamps that hold the blades onto the front of the disc, and the disc is rotated in steps through the exposed region until such time as blades in all the slots are changed. A considerable amount of debris produced during the chipping operation is left behind which must be removed from the machine before replacement blades are installed. The unwanted material that is left behind is generally tightly packed in the disc slots and caked upon the machine surfaces and requires among other things such as mechanical scraping and the application of high pressure air to dislodge it and clear it away from the machine. This, in turn, causes a great deal of dirt, dust and the like to be broadcast about the machine location which is difficult and time consuming to contain and clean up. In addition, these airborne particles can cause an eye injury or be inhaled by those working in the area and thus create a potential health hazard.
Attempts have been made to contain and clean up the debris created during the blade replacing procedure using such techniques as vacuuming but for the most part have met with little success or are far less efficient and are more time consuming than using high pressure air.